This invention relates to a detection device for an apparatus for chromatographic analysis such as a liquid chromatograph.
Detection devices comprising an optical system are commonly used for an apparatus for analysis such as a liquid chromatograph. Such a detection device is adapted to carry out the quantitative analysis of components of a sample by causing the sample separated in a column to pass through a cell together with a solvent, making a beam of light incident on the cell and measuring the light absorbance, the coefficient of refraction or phosphorescence.
When such an apparatus for analysis is used, the operator is required to wait for a significantly long period of time after the power switch for the apparatus is turned on or the source light is switched on until the temperature of the optical system or the light source becomes stabilized such that a reliable analysis can be started. Conventionally, the operator was required to keep watching the screen of a CRT or a plotter display during this wait period. If the operator is distracted or forgets to keep checking, the starting of the analysis may be unwittingly delayed. The same problem is also encountered with gas chromatographs.
It is therefore an object of this invention to provide a detection device for an apparatus for analysis capable of automatically starting a program of operations for analysis after the power for the apparatus is switched on such that the waste of time for waiting can be eliminated and the burden on the operator can be alleviated.
A detection device embodying this invention for an apparatus for carrying out material, analysis, with which the above and other objects can be accomplished, may be characterized as comprising not only a detector for outputting detection signals but also a stabilization judging, unit for measuring drift and noise of these detection signals overtime automatically and transmitting a start signal which permits the apparatus for analysis to start operations of analysis when the measured drift and noise become smaller than their respective standard values. Such a detection device may preferably further comprise a standard noise value setting unit for receiving detection signals at a detection wavelength while a standard sample is placed inside a detection cell, calculating a standard noise value on the basis of intensity of the detection signals, and transmitting the calculated standard noise value to the stabilization judging unit. If the apparatus for carrying out analysis is a chromatograph, the detection device may preferably further comprise a standard drift value setting unit for storing standard drift values corresponding to temperatures of the column of the chromatograph, retrieving one of stored standard drift values corresponding to measured temperature of the column when measurements are taken by the chromatograph and transmitting the retrieved standard drift value to the stabilization judging unit.